Keychain

For the cryptography concept, see Keyring (cryptography). For mobile phone application, see Key Ring (software). For the password management systems, see Keychain (Mac OS) and GNOME Keyring.

A keychain (/ˈkitʃeɪn/ ^ⓘ) (also keyring) is a small ring or chain of metal to which several keys, or fobs can be attached. The terms keyring and keychain are often used interchangeably to mean both the individual ring, or a combined unit of a ring and fob.

Three keys on a keyring with a promotional message

The length of a keychain or fob may also allow an item to be used more easily than if connected directly to a keyring. Some keychains allow one or both ends to rotate, keeping the keychain from becoming twisted, while the item is being used.

Keybearer with a keyring, 1605, from one of the Nürnberger Hausbücher [de]

Keyring

A key can be added to a keyring by forcing an end of the loop open and sliding the key along the spiral.

A key with a keyring and a simple text label keychain

A keyring or "split ring" is a circle cotter that holds keys and other small items sometimes connected to keychains. Other types of keyrings are made of leather, wood and rubber. These are the central component to a keychain.

Keyrings were invented in the 19th century by Samuel Harrison. ^[1] The most common form of the keyring is a single piece of metal in a 'double loop'. Either end of the loop can be pried open to allow a key to be inserted and slid along the spiral until it becomes wholly engaged onto the ring. Novelty carabiners are also commonly used as keyrings for ease of access and exchange. Often the keyring is adorned with a fob for self-identification or decor. Other forms of rings may use a single loop of metal or plastic with a mechanism to open and securely close the loop.

Key fob

A wooden key fob made in Finland

A key fob is a generally decorative and at times useful item many people often carry with their keys, on a ring or a chain, for ease of tactile identification, to provide a better grip, or to make a personal statement. Key fob can also specifically refer to modern electronic car keys, or smart keys, which serve as both a key and remote.

The word fob may be linked to the low German dialect for the word Fuppe, meaning "pocket"; however, the real origin of the word is uncertain. Fob pockets (meaning 'sneak proof' from the German word foppen) were pockets meant to deter thieves. A short "fob chain" was used to attach to items, like a pocket watch, placed in these pockets.^[2]

Access control key fobs

Security tokens from RSA Security designed as key fobs.

Access control key fobs are electronic key fobs that are used for controlling access to buildings or vehicles.^[3] They are used for activating such things as remote keyless entry systems on motor vehicles.^[4][5] Early electric key fobs operated using infrared and required a clear line-of-sight to function. These could be copied using a programmable remote control. More recent models use challenge–response authentication over radio frequency, so these are harder to copy and do not need line-of-sight to operate. Programming these remotes sometimes requires the automotive dealership to connect a diagnostic tool, but many of them can be self-programmed by following a sequence of steps in the vehicle and usually requires at least one working key.

Some retail establishments such as gasoline stations keep their bathrooms locked and customers must ask for the key from the attendant. In such cases the key often has a very large fob so that customers will not automatically pocket and walk off with the key after completing their ablutions. Key fobs offering added functionalities connected to online services may require additional subscription payment to access them.^[6]

Computer keychains

By analogy to the physical object, the terms keychain and keyring are often used for software that stores cryptographic keys. The term is used in GNU Privacy Guard to store known keys on a keyring. Mac OS X uses a password storage system called Keychain. A "keyring" is also the name of a password manager application working under the GNOME desktop manager (used for example in Ubuntu operating system). In cryptography a keyring is a database of multiple keys or passwords. There are also portable password manager programs, such as Keepass and KeePassX.

As a collectible item

Kinkaku-ji keychain from Japan, from a personal collection.

According to Guinness World Records, the largest collection of keychains consists of 62,257 items, achieved by Angel Alvarez Cornejo in Sevilla, Spain, as verified on 25 June 2016. His collection began at the age of 7. Due to the tremendous size of his collection he now stores his keychains in his garage and a rented warehouse.^[7] The previous record holder was Brent Dixon of Georgia, United States with the largest collection of keychains, at 41,418 non-duplicated ones.^[8]

See also

• Key finder